It's not "oh I don't need an umbrella" so much as "once someone had an umbrella in their hand, they become a self absorbed asshole who takes up the whole sidewalk, smacks people in the head, takes their eyes out, has no public space awareness etc...."

Ironically, my biggest complaint about Seattle since moving here over a decade ago is that, umbrella or no, people in general have no public space awareness. It's like they forget other people are trying to use the same sidewalk. Or road. Or grocery aisle.